Annular linear flow electromagnetic induction pumps for impelling electrically conducting liquid metals generally comprise an annular flow channel or duct which is surrounded by a column composed of a multiplicity of alternating annular stator coils and magnetic stator iron. This type of electromagnetic pump, commonly known as a single stator, annular linear flow induction pump, and its use in a liquid metal cooled nuclear fission reactor, is disclosed in U.S. Pat. No. 4,859,885, issued Aug. 22, 1989, and U.S. Pat. No. 4,882,514, issued Nov. 21, 1989.
However a more versatile linear flow electromagnetic pump design than the single stator system shown in the above patents comprises a double stator system. This type of electromagnetic pump comprises the single stator arrangement as shown in the aforesaid patents, which is additionally provided a second or inner stator arrangement concentrically contained and enclosed within the aforementioned central linear liquid flow channel or duct. A second stator column is also composed of a multiplicity of alternating annular stator coils and stator irons. In combination, the outer and inner, or double stators act upon the liquid linearly passing through the annular pump flow duct.
The double stator arranged electromagnetic pump design provides greater pumping capacity per pump unit size, or alternatively equal capacity provided by a smaller pump unit. Accordingly the double stator design pump has the advantage of greater efficiency and versatility, among others.
The disclosures and contents of the aforesaid patents, namely U.S. Pat. No. 4,508,677, U.S. Pat. No. 4,859,885 and U.S. Pat. No. 4,882,514, are each incorporated herein by reference.